Morphological and biochemical observations on cells derived from the in vitro differentiation of the embryonal carcinoma cell line PCC4-F.

The embryonal carcinoma cell line PCC4-F was shown to differentiate in vitro to a variety of cell types. A combination of light and electron microscopy and histochemical meth ods identifies or strongly suggests the presence of cardiac and skeletal muscle, fibroblasts, ciliated and nonciliated epithelial cells, endodermal yolk sac cells, neurally derived cells, and fat cells. Two cell lines were isolated from differ entiated cultures. Preliminary comparisons have been made between these cell lines and the undifferentiated em bryonal carcinoma cells. The derived cell lines produce an extracellular fibrous substance that gives a positive reac tion to the periodate-Schiff reagent indicating a glycoprotein nature. There are significant differences in the incor poration of D-[3H]glucosamine and L-[3H]fucose into soluble extracellular proteins when the derived cell lines are com pared with the embryonal carcinoma. These extracellular glycoproteins fall within narrow size classes. Enzyme stud ies indicate the presence of a new lactate dehydrogenase isozyme which is absent or greatly diminished in the derived cell lines. The specific activity of alkaline phosphatase is dramatically decreased in the derived cell lines, whereas those of acid phosphatase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase were not significantly different. Comparison of the derived lines with the prop erties of parietal endodermal yolk sac cells described by Lehman et al. (J. Cellular Physiol., 84: 13-28, 1974) sug gests that these new lines are very similar if not identical in properties.